The present inventive teachings relate generally to a ram fan assembly, and more particularly, an inner housing assembly included with a ram fan assembly.
Ram air fan (RAF) assemblies traditionally include a motor/bearing housing and an inner housing assembly. The motor/bearing housing typically contains one or more bearings coupled to a shaft for driving a RAF unit, and a motor coupled to the shaft for generating rotation thereof. The inner housing assembly includes an inlet connected to a cool air duct and an outlet connected in fluid communication with the motor/bearing housing to deliver cool air over the motor and/or bearings to prevent over-heating.
During operation of the RAF assembly, the ram fan assembly generates a ram air flow, which flows across the outer surface of the motor/bearing housing and the inner housing assembly. As the speed of the ram air flow increases, the inner housing assembly may realize a shear force that promotes the inner housing assembly to move laterally away from the motor/bearing housing. Consequently, the shear force may cause the outlet of inner housing assembly to become disengaged from motor/bearing housing.